Class vs Struct for data only?

Question

Is there any advantage over using a class over a struct in cases such as these? (note: it will only hold variables, there will never be functions)

class Foo { 
private:   
   struct Pos { int x, y, z };
public:    
   Pos Position; 
};

Versus:

struct Foo {
   struct Pos { int x, y, z } Pos;
};

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Similar questions:

• When should you use a class vs a struct in C++?
• What are the differences between struct and class in C++?
• When should I use a struct instead of a class?

Answer 1

There is no real advantage of using one over the other, in c++, the only difference between a struct and a class is the default visibility of it's members (structs default to public, classes default to private).

Personally, I tend to prefer structs for POD types and use classes for everything else.

EDIT: litb made a good point in the comment so I'm going to quote him here:

one important other difference is that structs derive from other classes/struct public by default, while classes derive privately by default.

Answer 2

One side point is that structs are often used for aggregate initialized data structures, since all non-static data members must be public anyway (C++03, 8.5.1/1).

struct A {  // (valid)
{
   int a;
   int b;
} x = { 1, 2 };

struct A {  // (invalid)
private:
   int a;
   int b;
} x = { 1, 2 };

class A {  // (invalid)
   int a;
   int b;
} x = { 1, 2 };

class A {  // (valid)
public:
   int a;
   int b;
} x = { 1, 2 };

class A {  // (invalid)
public:
   int a;
private:
   int b;
} x = { 1, 2 };